1. Centre d'imagerie Médicale, 47, Boulevard du Pont Rouge, 15000 Aurillac, France.
2. Department of Radiology, Hôpital Raymond Poincaré, Assistance Publique-Hôpitaux de Paris, Université Paris Ile-de-France Ouest, 104 Boulevard Raymond Poincaré, 92380 Garches, France.
3. Department of Radiation Oncology, Antoine Lacassagne Cancer Research Institute, 33, Avenue Valombrose, 06189 Nice Cedex 1, France.